COLOMBO, Nov 12 (AFP) - Sri Lanka's top general, Sarath Fonseka, the architect of the army's recent victory over Tamil rebels who was switched to a more ceremonial position, quit Thursday, a military source said.

Fonseka, who is widely tipped to challenge President Mahinda Rajapakse in the next elections, gave his resignation as chief of defence staff after a ceremony welcoming Myanmar's junta leader at the airport, the source said.

"He gave his letter of resignation this afternoon and expects the government to ensure his security because he was the main figure responsible for crushing Tamil Tigers," the source close to him said.